Continuously variable vehicle transmissions are generally identified by "CVT" and are, for example, known from EP,A1,0,451,887. Such CVT transmissions permit driving at low engine rpms. The adjustment of the transmission ratio generally takes place hydraulically and the required hydraulic pressure is supplied by a hydraulic pump driven by the vehicle engine. However, a sudden and very intense braking can lead to the situation that the CVT transmission still has a relatively low transmission ratio in some circumstances for a vehicle standstill because the volumetric displacement of the pump at low engine rpms is insufficient in the short braking time which is available in order to adjust the transmission to a high start transmission ratio. If the vehicle is at standstill, then the transmission cannot be adjusted so that the objective must be to always reach the start transmission ratio shortly before the vehicle comes to standstill.
In order to adjust the start transmission ratio at the end of the braking operation, the transmission can be adjusted as rapidly as possible to large transmission ratios when an intense deceleration is recognized. A torque converter is generally mounted between the vehicle engine and the CVT transmission and this torque converter can be bridged by a converter bridging clutch. For this reason, the rpm of the engine drops to the idle rpm at the instant at which the converter bridge clutch opens. At the very latest, it can be that the displacement volume of tine hydraulic pump is no longer adequate in order to adjust the transmission so that the vehicle comes to standstill with transmission ratios which are less than the start transmission ratio.
One possibility of solving this problem comprises driving the engine at an increased idle rpm during braking. However, this can remain only a very limited intervention because, during deceleration of the vehicle, in no case can a propulsion torque be effective on the wheels because of increased engine rpm.